Shell shot wad

ABSTRACT

An ammunition cartridge for use with a firearm, such as a shotgun or rifle, and which includes a shot shell wad having a cylindrical housing which has a forward or outer shot receiving chamber separated from the at least one innermost shot receiving chamber by a partition which is preferably integrally formed with the housing and wherein the projectiles or shot receiving chambers include a plurality of open conically shaped chamber portions that are in open communication with one another at an apex and base of each adjoining projectile or shot receiving chamber so that, upon firing of the cartridge, the projectiles or shot are directed centrally and forwardly relative to a centerline of the housing as the projectiles or shot separate from the innermost camber and exit an open end of the outer chamber.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention is directed to ammunition cartridges including shot shell wads wherein the cartridges are of a type used with shotguns and wherein the shot shell wads have a cylindrical body or housing structure including a separate charge receiving chamber and multi-sectional projectiles or shot receiving chambers. The chambers define inner portions of the wad, some of which are taper inwardly into open communication with intermediate or outer sections, so as to direct the projectiles or shot toward a centerline of the body or housing of the wad as such projectiles pass from one chamber to an adjacent chamber. In this manner, outward forces are created against the cylindrical walls of the wad and yet direct the projectiles or shot into a more compact formation as the projectiles or shot pellets exit a barrel of a firearm by reducing back pressure normally created by outer shot pellets within a wad on inner shot pellets therein when a cartridge is fired.

Brief Description of the Related Art

Shot shell wads made of plastic or paper have been developed for purposes of protecting the inner bore of a firearm, such as a rifle or shotgun, when cartridges containing projectiles such as steel shot are fired. The shot shell wads include a cylindrical housing defining an inner charge retaining chamber and outer shot retaining chamber. Upon firing, the plastic or paper wad protects the bore of the barrel as it travels along the bore with the shot pellets. To facilitate a separation of the wad from the shot pattern exiting the muzzle of the barrel, U.S. Pat. No. 6,260,484 to Billings, teaches forming lines of weakness in the cylindrical wall of the hosing of the wad in an area of the charge receiving chamber in order to allow a plurality of outwardly extending fins to be formed in the wad when a cartridge is fired. This prior art patent teaches to both control the trajectory of the wad and preventing tumbling of the wad so that the wad will not interfere with the shot pattern by slowing a velocity of the wad to cause an even or predetermined separation of the wad from the shot pattern. The use of this prior art shot shell wad also functions to retain the shot pellets in a more compact pattern until impact with a target.

With conventional shot shell wads, upon being fired, the outermost shot pellets within a wad apply a crushing force back against underlying or inner shot pellets which deforms the underlying shot pellets. This crushing force results in a change in the flight characteristics of the shot pellets. The deformation of the shot pellets disperses the underling shot laterally outwardly thereby preventing a compact formation of the pellets as they separate from the shot shell wad when exiting a barrel of a firearm. To offset this backpressure effect, it has been known to add finely ground plastic particles or soap particles to fill voids between the shot pellets within the shot shell wad. However, this has not fully prevented the backpressure effect on the inner shot pellets by the outer shot pellets.

Some other examples of prior art are disclosed in U.S. Pat. No. 34,806 to Budd, U.S. Pat. No. 2,368,029 to Knight, U.S. Pat. No. 3,279,375 to Herter, U.S. Pat. No. 3,299,813 to Rickey, U.S. Pat. No. 3,400,660 to Malter, U.S. Pat. No. 3,656,433 to Thrailkill et al, U.S. Pat. No. 3,092,026 to Williams et al, U.S. Pat. No. 3,132, 588 to Schafer, U.S. Pat. No. 3,422,761 to Whitmore, U.S. Pat. No. 3,516,360 to U.S. Pat. No. 3,599,568 to Shellmett, U.S. Pat. No. 3,974,775 to Kerzman et al, U.S. Pat. No. 4,295,426 to Genco et al, U.S. Pat. No. 4,760,793 to Herring et al, U.S. Pat. No. 4,996,923 to Theising, U.S. Pat. No. 5,874,689 to Alkhatib et al, U.S. Pat. No. 6,202,561 to Head et al, and U.S. Pat. No. 6,367,388 to Billings. Examples of foreign patents are DE 2010488, FR 1526972 and FR 2559892.

SUMMARY OF THE INVENTION

The present invention has been developed to control pressures developed between layers of shot pellets in a shot shell wad of a cartridge so as to create better shot formations and trajectories as the shot pellets separate from a shot shell wad upon firing of the cartridge. The invention has also been developed to facilitate the separation of the shot pellets from the shot shell wad by not only controlling the pressure applied by the shot pellets within the wad so as to more evenly distribute pressures developed within the layers of shot pellets within the wad but to also more equally distribute internal forces created by the shot pellets along the inner side walls of the shot shell wad as the shot is forced against the inner walls of the wad upon ignition of a charge within the charge chamber of the shot shell wad or cartridge.

The shot shell wads of the present invention are configured having a conically shaped innermost shot pellet receiving chamber which includes a concave base wall that is oriented toward a restricted opening at an outlet of the innermost chamber and with side walls of the innermost chamber tapering inwardly in a conical manner from the outermost portions of the base wall toward the restricted opening in the upper end of the innermost chamber. In a first embodiment of the invention, a single conically shape innermost shot pellet receiving chamber communicates directly with an outermost shot receiving chamber which also has a concavely configured base wall but which is generally cylindrical along the side walls thereof toward a discharge end of the wad. The restricted opening for the innermost chamber is formed in the concave base wall of the outermost chamber. The purpose of the base wall, tapering side walls and restricted opening of the innermost chamber is to distribute forces against the side walls of the shot shell wad and to limit the back pressure from the shot pellets in the outermost chamber on the shot pellets within the innermost chamber when a cartridge is fired.

In the first embodiment, pressure from the shot pellets in the outermost chamber is offset by the inwardly extended concave base wall of the outermost chamber. Further, by changing the configuration of the base wall of the outermost chamber and/or the size of the restricted opening therein, pressure distributions can be altered between the shot pellets in the outermost and innermost chambers to thereby prevent spreading of the shot pellets within the chambers as the shot shell wad separates from the shot pellets as the wad exits a muzzle of a firearm.

A further benefit of the present invention is the manner in which the shot pellets within the tapered walls of the innermost chamber act to force the side walls of the shot shell wad to spread outwardly as the shot pellets are forced against the tapered side walls of the chamber when a cartridge is fired. As the shot pellets are compacted in a somewhat conical pattern oriented toward an upper restricted opening at the apex of the inverted cone of the innermost chamber, the pressure of the shot pellets is directed on the inwardly tapered side walls of the innermost chamber causing the side walls to more easily and quickly separate from the shot pellets and thereby facilitate separation of the wad from the shot pellets as the shot shell wad exits the muzzle of a firearm and thereby prevents tumbling interference of the wad with a formation of the fired shot pellets.

In addition to the foregoing, it is believed that by forcing the shot pellets inwardly toward a center axis of the shot shell wad upon firing, that the formation of the pellets exiting from the muzzle of a firearm will be more compact at greater distances from the firearm.

In another embodiment of the invention, at least one secondary inner shot pellet receiving chamber will communicate downstream from the innermost shot pellet receiving chamber to receive the shot pellets from the innermost chamber. Such secondary inner shot pellet receiving chambers will be configured substantially the same or the same as the innermost chamber with the exception of the restricted exit opening for the innermost chamber is formed in the base wall of each secondary inner chamber. The number of secondary chambers may be from one to a plurality. Shot pellets from the secondary shot pellet receiving chambers communicate with the outermost chamber. As with the first embodiment, the structures of the secondary chambers both reduce backpressure on the shot in innermost and secondary inner chambers and also help in spreading the side walls of the shot shell wad to prevent interference of the wad with a shot pattern separating from the wad.

In each embodiment of the invention, an outer portion of a hull surrounding the shot shell wad is normally crimped over an open end of an open end portion of the outermost shot receiving chamber to retain the shot pellets within the shot shell wad.

In some embodiments of the invention, to further facilitate a non-interfering relationship between the shot shell wad and the shot pellets being fired, a plurality of lines of weakness or score lines may be made in the body or housing of the shot shell wad. The lines of weakness are formed extending from the open end of the shot shell wad toward an inner base portion of the wad. In this manner, the walls of the housing of the shot shell wad will be caused to flare outwardly as the wad exits the muzzle of a firearm due both by the pressure of the shot impacting the tapered walls of the shot shell wad housing and by air pressure against the wad, thus maximizing separation of the shot shell wad from the shot formation as the shot shell wad exits a muzzle of a firearm.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the invention will be had with respect to the accompanying drawings wherein:

FIG. 1A is an enlarged cross sectional view of one embodiment of a new shot shell wad for use with cartridges for firing shot pellets wherein the shot shell wad is mounted within a hull of cartridge;

FIG. 1B is an enlarged cross sectional view of another embodiment of shot shell wad in accordance with the invention;

FIG. 2 is a view taken along line 2-2 of FIG. 1A showing a crimped end of a cartridge hull incorporating a shot shell wad of the invention;

FIG. 3 is a view taken along line 3-3 of FIG. 1A showing the base end of a cartridge incorporating a shot shell wad of the invention;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 6 showing notched slits formed in the sidewall of a shot sell wad housing in accordance with the invention;

FIG. 5 is a cross section similar to FIG. 4 showing lines of weakness formed in the side wall of the shot shell wad housing;

FIG. 6 is a perspective view of the housing of the shot shell wad showing lines of weakens formed in the sidewalls thereof;

FIG. 7 is a perspective view of a shot shell wad of the invention illustrating how the body of the housing of the wad will flare open as the wad exits a muzzle of a firearm when fired;

FIG. 8A illustrates an alternate embodiment of the shot shell wad shown in FIG. 1A depicting an alternate innermost base wall; and

FIG. 8B illustrates an alternate embodiment of the shot shell wad shown in FIG. 1B depicting an alternate base wall.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With continued reference to the drawings, an ammunition cartridge, such as a shot gun shell 10, is shown in FIG. 1A as being positioned within an annular rim seat 11 to a rear of a bore 12 of a barrel 13 of the firearm. The cartridge includes a cylindrical casing or hull 14 which is closed at its forward end by crimped end segments 15. The hull is formed of any conventional material, such as plastic or cardboard. The casing is seated within an annular metal cap 16 of a charge forming chamber 17 which includes a central primer 19. Mounted within the hull is a shot shell wad 18 which houses projectiles such as conventional metal shot pellets 20 and functions to protect the inner surface of the barrel from the shot pellets when the cartridge is fired. After the shot shell wad and pellets exit the barrel, the wad separates from the pellets and the pellets proceed to a target.

The shot shell wad 18 of the present invention is constructed to prevent backpressure damage to the pellets 20 when the cartridge is fired to thereby control adverse spreading of a pattern of shot pellets when the pellets separate from the shot shell wad as the pellets and wad exit the barrel of the firearm. To accomplish this, the present invention includes at least two shot retaining chambers which communicate with one another. In the embodiment shown in FIG. 1A, three chambers are shown within the shot shell wad 18 including an innermost chamber 22, an intermediate chamber 23 and an outer chamber 24. Each of the innermost and intermediate chambers is conically configured having arcuate concave base walls 25 and 26, respectively, and forwardly and inwardly tapering side walls 27 and 28, respectively. An opening 30 is provided between the innermost and intermediate chambers at an exit end of the innermost chamber. A further opening 31 is provided at an exit end of the intermediate chamber between the intermediate chamber and the outer chamber 24.

The configuration of the outer chamber includes an arcuate concave base wall 32 and a cylindrical chamber wall 33 that extends to an open end 34 that is normally closed by the crimped end segments 15 of the shell hull 14 as shown in FIG. 2.

The configuration of the shot retaining chambers of the present invention are to reduce or prevent backpressure crushing of the pellets within the innermost and intermediate chambers from forces exerted by the layers of shot within the outer chamber when the cartridge is fired. The backpressure is countered by the inwardly extending and curved base walls of the chambers. Also, the outwardly and inwardly tapering side walls of the innermost and intermediate chamber tends to direct the shot moving through the opening between the chambers inwardly toward a longitudinal axis A-A of the shot shell wad and thereby obtain a more controlled and compact formation of the shot pellets that exit the muzzle of the firearm. The shape of the side walls of the innermost and intermediate chamber also functions to enhance the separation of the shot shell wad from the shot pattern as both the wad and the shot exit the muzzle of the firearm. As the shot pellets move through the innermost and intermediate chambers, the shot pellets direct force against the tapered walls which results in urging the side walls of the cambers to spread apart as the wad exits the barrel.

To further aide in the outwardly spreading of the side walls of the shot shell wad, lines of weakness 35 are provided in the outer side cylindrical wall 36 of the body or housing 37 of the wad as shown in FIGS. 4-6 of the drawings. The lines of weakness may be scored or partially cut in the outer wall of the body of the shot shell wad 18 and extend from adjacent the base wall 25 of the innermost chamber 22 to the end 34 of the outer chamber 24 and are generally parallel to the longitudinal axis A-A of the wad. The number of lines of weakness may be varied, however, the lines should be generally equally spaced relative to one another about the circumference of the outer wall of the body. Four lines of weakness are shown in the drawings. After the shot shell wad 18 exits the muzzle of the barrel, the side walls will flare outwardly into a plurality of segments 38 and will thus aide in the separation of the wad from the shot 20 and thereby prevent interference to the shot pattern by impact the tumbling wad.

In another embodiment of the invention as shown in FIG. 1B, only a single innermost chamber 22′ is shown which communicates directly to an outer chamber 24′. The innermost chamber 22′ is conically configured having an arcuate concave base wall 25′ and forwardly and inwardly tapering side walls 27′. An opening 30′ is provided between the inner and outer chambers at an exit end of the inner chamber. The configuration of the outer chamber includes an arcuate concave base wall 32′ and a cylindrical chamber wall 33′ that extends to an open end 34′ that is normally closed by the crimped end segments 15 of the shell casing or hull 14 as shown in FIG. 2. In this embodiment, the arcuate concave base wall 25′ and the tapering side walls 27′ provide the same functions as those described with respect to the first embodiment to prevent crushing of the shot pellets and by guiding the pellets into a more compact configuration closer to the longitudinal axis A-A of the shot shell wad.

It should be noted that by altering the slope angle of the side walls of the innermost and intermediate chambers of the invention a degree of compactness of the shot pattern upon firing a cartridge may be changed. Also, by changing diameter of the openings between the shot chambers of the invention, the effect of backpressure resistance and shot compactness may also be altered. It is preferred, however, that the diameter not be generally less that approximately three times the diameter of the shot pellets nor greater than five to six times the diameter of the shot pellets.

It should also be noted that the invention may also be practiced using more than the two inner and intermediate shot chambers in the first embodiment as shown in FIG. 1A. Thus three or four inner chambers are envisioned within the teachings of the present invention.

Alternative embodiments of the preferred embodiment are considered in FIGS. 8A and 8B. The embodiment illustrated in FIG. 8A is an alternate embodiment of, and has identically numbered elements as, the FIG. 1A embodiment. However, the shape of base wall 25 differs between the embodiments of FIGS. 1A and 8A. In FIG. 1A, the base wall 25 is arcuate and concave, whereas the base wall 25 of FIG. 8A is linear across a cross-sectional view, being flat instead of curved. Those skilled in the art can appreciate that differently shaped base walls 25 of the innermost shot receiving chamber may be used to achieve different applications and purposes of the shell shot wad. The differently shaped base wall 25 in FIGS. 1A and 8A do not negate the essential inventive concept of the disclosed embodiments of the shell shot wad, namely that the diameter of openings 30 and 31 are narrower, or smaller, than a diameter of chambers 22, 23, and 24. Additionally, other similarly shaped base walls are possible, such as an angled base wall, convex base wall, etc. Further, the differently shaped innermost shot receiving base wall 25 may be included in embodiments including two or more total chambers, and wherein such two or more chambers are similarly or differently shaped.

Further, FIG. 8B illustrates an alternate embodiment of the shell shot wad depicted in FIG. 1 B, with identically numbered elements. The embodiment of FIG. 8B shows another possible shape of the base wall 32′, or a base wall other than of the innermost shot receiving chamber, such that the base wall tapers outwardly mirroring the inwardly tapering side walls 27′. Again, the shape of the inwardly tapering side walls 27′ and base wall 32′ specifically shown in embodiments illustrated in FIGS. 1A, 1B, 8A, or 8B is not essential to the disclosure. As long as the diameter of the opening 30′, and any similar opening possible with three or more chambers, is narrower, or smaller, than a diameter of chambers 22′ and 24′, the inventive concept of the shell shot wad is preserved.

A person skilled in the art would appreciate that the base walls 25, 26, 32, 25′, 32′ and inwardly tapering side walls 27, 28, and 27′ may be formed in any combination of the embodiments presented in FIGS. 1A, 1B, 8A, and 8B. Further, other shapes and combinations of said elements are possible to achieve the common structure of narrowed openings between each of two or more chambers to create a choke point and to channel shot along an axis A-A and form a compact shot pattern. The embodiments depicted in FIGS. 8A and 8B have been provided only to illustrate several possible shapes of a shell shot wad falling within the inventive concept of the present disclosure. FIGS. 1A, 1B, 8A and 8B do not limit other possible embodiments as described herein.

The foregoing description of the preferred embodiments of the invention has been presented to illustrate the principles of the invention and not to limit the invention to the particular embodiments illustrated. It is intended that the scope of the invention be defined by all the embodiments encompassed within the scope of the following claims and their equivalents. 

1. A shot shell wad for use with an ammunition cartridge including a hull and a charge chamber, the shot shell wad comprising a generally cylindrical housing of a size to be seated within the cartridge hull with an inner end thereof adjacent the charge chamber of the cartridge, the hull having a cylindrical outer wall and a shot discharge end, an innermost shot receiving chamber formed within the housing and having an innermost base wall from which extend outer extending and inwardly tapering conical side walls, an opening at an apex of the conical side walls communicating with an outer shot receiving chamber, the outer shot receiving chamber having an outermost base wall with the opening being generally centrally therein, the outer chamber having a generally cylindrical side wall extending from the outermost base wall thereof to the shot discharge end of the housing.
 2. The shot shell wad of claim 1 including a plurality of lines of weakness formed in the outer wall of the housing and wherein the lines of weakness are generally equally spaced relative to one another about a circumference of the outer wall of the housing.
 3. The shot shell wad of claim 1 including at least one intermediate shot receiving chamber formed between the innermost shot receiving chamber and the outer shot receiving chamber, each intermediate shot receiving chamber having an intermediate base wall from which extend outer extending and inwardly tapering conical side walls, an opening at an apex of the conical side wall of the each intermediate shot receiving chamber that directly communicates with the outer chamber through the outermost base wall of the outer chamber.
 4. The shot shell wad of claim 3 including a plurality of lines of weakness formed in the outer wall of the housing and wherein the lines of weakness are generally equally spaced relative to one another about a circumference of the outer wall of the body.
 5. An ammunition cartridge for shooting shot pellets comprising a casing and a charge chamber, a shot shell wad including a generally cylindrical housing of a size to be seated within the cartridge casing with an inner end thereof adjacent the charge chamber of the cartridge, the housing having a cylindrical outer wall and a shot discharge end, at least one innermost shot receiving chamber formed within the housing and having a concavely arcuate base wall from which extend outer extending and inwardly tapering conical side walls, an opening at an apex of the conical side walls communicating with an outer shot receiving chamber, the outer shot receiving chamber having an outermost concavely arcuate base wall with the opening being generally centrally therein, the outer chamber having a generally cylindrical side wall extending from the outermost base wall thereof to the shot discharge end of the housing.
 6. The ammunition cartridge of claim 5 including a plurality of lines of weakness formed in the outer wall of the body and wherein the lines of weakness are generally equally spaced relative to one another about a circumference of the outer wall of the housing of the shot shell wad.
 7. The ammunition cartridge of claim 5 including an intermediate shot receiving chamber formed between the at least one innermost shot receiving chamber and the outer shot receiving chamber of the shot shell wad, the intermediate shot receiving chamber having an intermediate concavely arcuate base wall from which extend outer extending and inwardly tapering conical side walls, another opening at an apex of the conical side wall of the intermediate shot receiving chamber that directly communicates with the outer chamber through the outermost base wall of the outer shot receiving chamber.
 8. The ammunition cartridge of claim 7 including a plurality of lines of weakness formed in the outer wall of the housing of the shot shell wad and wherein the lines of weakness are generally equally spaced relative to one another about a circumference of the outer wall of the housing. 